Condensed Consolidating Financial Statements (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating activities:
Net income (loss)	$ 1,575	$ (5,476)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	15,736	16,564
Change in value of life insurance contracts	(161)	(158)
Other changes in noncurrent assets and liabilities	6,535	(9,034)
Changes in operating assets and liabilities:
Other changes, net		8,577
Changes in operating assets and liabilities:	3,204
Net cash provided by operating activities	26,889	10,473
Investing activities:
Utility plant expenditures	(35,047)	(24,620)
Purchase of life insurance		(1,674)
Changes in restricted cash and other changes, net	(26)	418
Net cash (used in) investing activities	(35,073)	(25,876)
Financing Activities:
Short-term borrowings	30,000	22,200
Repayment of short-term borrowings		(5,000)
Proceeds from long-term debt	50
Repayment of long-term debt	(338)	(460)
Advances and contributions in aid of construction	1,777	2,194
Refunds of advances for construction	(1,574)	(1,535)
Dividends paid to non-affiliates	(8,007)	(7,758)
Net cash provided by financing activities	21,908	9,641
Change in cash and cash equivalents	13,724	(5,762)
Cash and cash equivalents at beginning of period	19,587	27,506
Cash and cash equivalents at end of period	33,311	21,744
Consolidating Adjustments
Operating activities:
Net income (loss)	(1,390)	5,697
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity earnings of subsidiaries	1,405	(5,681)
Dividends received from affiliates	(8,007)	(7,758)
Depreciation and amortization	(25)	(27)
Other changes in noncurrent assets and liabilities	94	11
Changes in operating assets and liabilities:
Changes in operating assets and liabilities:	(84)
Net cash provided by operating activities	(8,007)	(7,758)
Investing activities:
Investment in affiliates	1,000
Changes in affiliate advances	667	1,660
Proceeds from affiliates long-term debt	(243)	(230)
Net cash (used in) investing activities	1,424	1,430
Financing Activities:
Investment from affiliates	(1,000)
Changes in affiliate advances	(667)	(1,660)
Repayment of affiliates long-term borrowings	243	230
Dividends paid to affiliates	8,007	7,758
Net cash provided by financing activities	6,583	6,328
Parent Company
Operating activities:
Net income (loss)	1,575	(5,476)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity earnings of subsidiaries	(1,405)	5,681
Dividends received from affiliates	8,007	7,758
Depreciation and amortization	57	43
Other changes in noncurrent assets and liabilities	1,109	772
Changes in operating assets and liabilities:
Other changes, net		(229)
Changes in operating assets and liabilities:	(1,151)
Net cash provided by operating activities	8,192	8,549
Investing activities:
Investment in affiliates	(1,000)
Changes in affiliate advances	(3,220)	(2,989)
Proceeds from affiliates long-term debt	243	230
Net cash (used in) investing activities	(3,977)	(2,759)
Financing Activities:
Short-term borrowings		2,200
Repayment of short-term borrowings		(5,000)
Dividends paid to non-affiliates	(8,007)	(7,758)
Net cash provided by financing activities	(8,007)	(10,558)
Change in cash and cash equivalents	(3,792)	(4,768)
Cash and cash equivalents at beginning of period	4,108	5,280
Cash and cash equivalents at end of period	316	512
Cal Water
Operating activities:
Net income (loss)	2,030	(4,520)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	14,575	15,424
Change in value of life insurance contracts	(161)	(158)
Other changes in noncurrent assets and liabilities	10,717	(9,176)
Changes in operating assets and liabilities:
Other changes, net		7,582
Changes in operating assets and liabilities:	(2,185)
Net cash provided by operating activities	24,976	9,152
Investing activities:
Utility plant expenditures	(33,793)	(22,896)
Changes in affiliate advances	2,725	1,510
Purchase of life insurance		(1,674)
Changes in restricted cash and other changes, net	(26)	418
Net cash (used in) investing activities	(31,094)	(22,642)
Financing Activities:
Short-term borrowings	30,000	20,000
Changes in affiliate advances	1,309	356
Repayment of long-term debt	(197)	(304)
Advances and contributions in aid of construction	1,759	1,735
Refunds of advances for construction	(1,573)	(1,521)
Dividends paid to affiliates	(7,909)	(7,469)
Net cash provided by financing activities	23,389	12,797
Change in cash and cash equivalents	17,271	(693)
Cash and cash equivalents at beginning of period	13,929	20,790
Cash and cash equivalents at end of period	31,200	20,097
All Other Subsidiaries
Operating activities:
Net income (loss)	(640)	(1,177)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	1,129	1,124
Other changes in noncurrent assets and liabilities	(5,385)	(641)
Changes in operating assets and liabilities:
Other changes, net		1,224
Changes in operating assets and liabilities:	6,624
Net cash provided by operating activities	1,728	530
Investing activities:
Utility plant expenditures	(1,254)	(1,724)
Changes in affiliate advances	(172)	(181)
Net cash (used in) investing activities	(1,426)	(1,905)
Financing Activities:
Investment from affiliates	1,000
Changes in affiliate advances	(642)	1,304
Repayment of affiliates long-term borrowings	(243)	(230)
Proceeds from long-term debt	50
Repayment of long-term debt	(141)	(156)
Advances and contributions in aid of construction	18	459
Refunds of advances for construction	(1)	(14)
Dividends paid to affiliates	(98)	(289)
Net cash provided by financing activities	(57)	1,074
Change in cash and cash equivalents	245	(301)
Cash and cash equivalents at beginning of period	1,550	1,436
Cash and cash equivalents at end of period	$ 1,795	$ 1,135